R33 Turbo Muffler

I have a Skyline R33. It has the 2.5 Liter engine, no turbo. What kind of muffler could I put on it. I live in Japan and I was going to buy a muffler but the Japanese lady told me it wouldn't work on my Car because it was meant for a turbo Skyline. Does anyone know if that is true?? Could I use a turbo muffler on My GTS. Or would my car run rough? Thanks

you can put it on... i mean... it'll fit.
but with the na motor you need that back pressure... its may not run rough but you wont gain much power... you might lose power